(From company literature) Tamrac 5749 Velocity 9 Pro Sling Pack. The Velocity 9 - Pro Sling Pack is a larger version of our popular Photo Sling Pack. It can be carried comfortably like a backpack, but can be swung around to the front to provide quick access to a pro-sized 35mm or digital SLR like a Nikon F5 and D1 or Canon’s EOS 1V and 1D with a 200mm zoom lens attached. A well-padded sling strap comfortably distributes the weight, but need not be removed to quickly access photo equipment. Outside, a large mesh pocket is ideal for carrying an energy bar or water bottle, while organizer pockets inside keep a mobile phone, PDA, or photo accessories within reach. A smooth nylon pocket inside the lid stores filters. Compatible with Tamrac’s Modular Accessory System™ components to customize this pack with Tamrac accessories.

Specifications:

Type: Sling Pack

Available Colors: Black, Blue

Outer Fabric: Unspecified

Type of Closure: Quick release buckle

Capacity: 1 pro-sized digital or film SLR with long zoom lens attached, additional lenses and a flash

I've carried Tamrac bags for many many years, and really enjoy their quality and ergonomics. This particular bag is fantastic for travel; I've carried it for 10-20 hours a day in Washington DC and Venice, Italy. The hip straps are a great relief as the day wears on and the walking continues.

Here is a gallery that shows the bag next to my big Domke bag. The Domke has its own advantages, but comfort in the field does not compare.http://www.pbase.com/deanzat/velocity_9
And since everyone asks, the lobster on the Domke bag keeps the cats from sleeping on it.